Your first photo looks close to 30* and the hang calculator should be on the mark.
So.....my assumption is that you got the hammock length from GT's "specs". That's your mistake. That measurement is usually given for the raw material before hemming, etc.
My GT UL measures ~105" so 83% of that is 87" and probably closer to what your ridgeline should be.
With all of that said, 83% is only a suggested starting point (that many hangers find to be perfect). What you are attempting to do is find the most comfortable hang and set your ridgeline for that length so it can be easily repeated.
The only thing you probably need to do is shorten the ridgeline to match your hang. I'll bet it's close to 87".